Speaking with BBC, Zimmer made it clear that he's scored his last superhero movie...

"I have officially retired from the superhero business...“I did ‘Batman Begins’ with Chris [Nolan] 12 years ago, so ‘The Dark Knight Trilogy’ might be three movies to you, to me it was 11 years of my life."

He said that his work with Junkie XL on the 'Batman v Superman' score was more a challenge, and is what drove him to this decision.

“This one was very hard for me to do, to try to find new language."

This may be a good thing, anyway. Zimmer's music was beginning to sound a little formulaic, and bringing in another composer could be a way to give the films a different texture. Next up for him are Ron Howard's Inferno and rejoining Nolan for Dunkirk.